Extreme pressure lubricant



Patented Sept. 10, 1940 UNITED STATES PATENT OFFICE EXTREME PRESSURELUBRICANT of Delaware No Drawing; Application November 22, 1937, Se-

rial No. 175,882.

8 Claims.

This invention relates to lubricants suitable for lubrication underextreme pressure conditions, dealing more particularly with minerallubricating oils containing small amounts of organic sulfonyl halidesproduced from aromatic mineral oils. The present invention is acontinuation-in-part of that disclosed in our application Serial No.69,163, filed March 16, 1936, in which we disclosed mineral lubricantscontaining small amounts of said sulfonyl halides, i. e., compoundscontaining the radical SO2X attached to an organic grouping where X is ahalide, such as methylene sulfonyl chloride, benzene sulfonyl bromide,naphthalene sulfonyl chloride, etc. It was shown that these organicsulfonyl halides are powerful extreme pressure compounds, superior intheir effect in the matter of raising the load carrying capacities oflubricating oils to which they are added, over other compoundscontaining the same number of the same elements in diflerentconfigurations. It was also shown that many of the organic sulfonylhalides are very resistant to hydrolysis so that the danger of corrosionmay be exceedingly small, if at all existing.

Now we have discovered that sulfonyl halide mixtures prepared fromnormally liquid asphaltfree aromatic mineral oil fractions which aresoluble in so-called naphthenic solvents, such as furfural, at atemperature below 50 C. and boil substantially above gasoline range (50%or less distilling below 400 F. by A. S. T. M. method), are in manyrespects superior extreme pressure compounds than the sulfonyl halidesheretofore proposed. We have found that such mixtures not only possessequal or superior extreme pressure properties and greater resistance tohydrolysis than the best of the sulfonyl halides disclosed in saidapplication Serial No. 69,163, flied March 16, 1936, but in additionpossess the unique property of positively inhibiting corrosion ofnormally corrosive lubricating oils.

Suitable aromatic mineral oil fractions used in the preparation of themixed sulfonyl halides of this invention may be obtained for instancefrom highly aromatic mineral oils such as Borneo crude oil, crackingrecycle oil, or coal tar oils by suitable distillation to removegasoline, asphalts and tar; or from naphthenic petroleum oil fractionsof the proper boiling range such as kero- 50 sene, gas oil, lubricatingoil distillate, by extrac- In the Netherlands March 19,

tion with a selective solvent for aromatic hydrocarbons such as liquidS02, furfural, phenol, nitrobenzene, BB dichlorethyl ether, crotonaldehyde, etc. For instance a fraction which was excellently suited forour purposes was prepared by extracting a kerosene obtained bydistillation from a naphthenic crude oil, with liquid S02 and removingthe S02 from the extract. This particular fraction had a-boiling rangeof 385 to 575 F. and proved to contain 50% aromatic rings, naphthenerings and 40% alkyl radicals, most of which were saturated. The presenceof relatively large percentages of olefines as found in cracking recycleoils, however, is not objectionable.

The suitable aromatic mineral oil fractions are then converted to thesulfonyl halides by any of the conventional methods used for producingsuch sulfonyl halides. Probably the most convenient procedure comprisestreating the aromatic fraction with an excess of chlorsulfonic acidhaving the formula ClSOsH, at about normal room temperature, preferablyin the presence of a substantial amount of carbon tetrachloride or othersubstantially inert mutual solvent for the reactants.

For example a solution of 200 grams carbon tetrachloride containing 25grams chlorsulfonic acid was cooled to 50 F. A solution of 14 grams ofan aromatic kerosene extract in one-third its own volume of carbontetrachloride was slowly admixed to the chlorsulfonic acid solutionwhile stirring and cooling, approximately to maintain the originaltemperature. After completed admixture stirring was continued for onehour at the same temperature and thereafter the reaction mixture wasallowed to stand for 24 hours without further cooling. Two layersformed, a bottom sludge layer and a larger top layer comprising thecarbon tetrachloride solution. The layers were separated and the carbontetrachloride solution was poured on ice to effect hydrolysis andseparation of unreacted chlorsulfonic acid. The aqueous acid layer wasremoved and the remaining carbon tetrachloride solution was twice washedwith water. During the washing further products of hydrolysis separatedin the form of a dark brown liquid which was allowed to settle and wasthen removed. The purified carbon tetrachloride solution was dried anddistilled to remove the solvent and to recover the mineral sulfonylchlorides in substantially pure form. Last traces of solvent wereexpelled by passing mtrogen through the distillation residue for 1 hourat about 260 F. A light yellow mobile liquid was obtained whichconsisted essentially of the desired sulfonyl chloride mixture and hadthe following properties:

Saponiflcation number 328 Chlorine content per cent" 10.4 Unsaponifiablematter do 6.0

Other methods for producing the petroleum sulfonyl halides comprisepreparing the sulfonic acids first by sulfonation of suitable mineraloil fractions and then treating the sulfonic acid so produced with ahalogenating reagent capable of replacing acidic hydroxyl radicals withhalides, such as PCls, SbCls, etc.

Solutions of 2% of the yellow liquid obtained above in minerallubricating oils were prepared and tested for extreme pressureproperties in several of the recognized extreme pressure testingmachines, and for anti-corrosiveness in the Underwood corrosion testingapparatus, as shown in the following examples. For the purpose ofcomparison, data for similar solutions of B naphthalene sulfonylchloride are also given.

In the Boerlage four-ball apparatus described in Engineering vol. 136(1933) page 46, the results were as follows:

'AKE aromatic kerosene extract.

The Floyd tester imitates to some extent the condition of a journal in asliding bearing. A steel shaft M; inch in diameter is driven by a motorby way of a retarder, so that the shaft revolves at the rate of 100 R.P. M. By means of an hydraulic plunger, an upper bearing cap is pressedupon this shaft with a known force.

There is another bearing cap underneath which supports the journal. Thebearings and the shaft are made of S. A.-E. 1112 "screw stock. The oilpressure is measured on the plunger by a pressure gauge in lbs. per sq.inch and this reading has to be multiplied by the factor 76.97 to findthe pressure in lbs. per sq. inch of the projected bearing surfaces.

In this tester the straight mineral oil permitted a load of 200 poundsonly, before the shearing pin broke. 2% B naphthalene sulfonyl chlorideraised the permissible load to 300 pounds, and with 2% aromatic keroseneextract sulfonyl chloride in the lubricating oil, the pressure could beraised to 600 pounds.

Anti-corrosion properties. were evaluated by the Underwood corrosiontest which consists of pumping the test oil for 5 hours at 320 F. in thepresence of oxygen and a small amount of lead naphthenate as corrosionaccelerator over a set of four half bearings, two of cadmium silveralloy and two of copper-lead alloy. At the end of this time the loss inweight of the bearings and the acid number of the oil are measured. V

The oil used in these tests was a solvent refined West Texas lubricatingdistillate which had a neutralization number. of .1 and proved to bequite corrosive in actual iulerication service. Results of the testswere as follows:

'AKE=aromstio kerosene extract.

The anti-corrosive action of our sulfonyl halides appears to beindependent of the nature of the corrosiveness of the lubricating oil.In other words it is immaterial whether the corresiveness is due-merelyto the absence of natural corrosion inhibitors, as the result of whichmetals receive insuiiicient protection from oxygen, moisture and acidicgases contained in the surrounding atmosphere; or whether it is due tothe presence of corrosive substances such as corrosive sulfur compounds,acids, etc.; or whether it is of a galvanic nature. In all cases asubstantial reduction of corrosiveness has been observed upon additionof the sulfonyl halides of this invention to corrosive lubricating oils.

The amounts of sulfonyl halides to be added to lubricating oils varywith the requirements which the oils must meet. In general the amountsadded are well below 5% and preferably are between .1 and 2%.

While in the foregoing examples we have shown the efiect of sulfonylchlorides only, it shall be understood that other aromatic mineral oilssulfonyl halides, namely, the fluorides, bromides and iodides are alsosuitable although the chlorides are preferred as being in general themost effective and the most stable.

Moreover, the sulfonyl halides of this invention may be used incombination with other compounds such as oiliness compounds orthickeners capable of producing greases, or ring sticking inhibitors forDiesel engine lubricating oils such as the salts of polyvalent lightmetals and aromatic fatty acids, naphthenic acids, etc.

We claim as our invention:

1. A substantially non-corrosive lubricant comprising a predominatingquantity of a mineral lubricating oil and a small quantity of mixedorganic sulfonyl halides prepared from an aromatic normally liquidmineral oil fraction soluble in liquid S02 and boiling substantiallyabove gasoline boiling range.

2. A substantially non-corrosive lubricant comprising a predominatingquantity of a mineral lubricating oil and a small quantity of mixedorganic sulfonyl halides prepared from an aromatic mineral oil fractionsoluble in liquid SO: and free from asphalt and boiling substantiallyabove gasoline boiling range.

3. A substantially non-corrosive lubricant comprising a predominatingquantity of a mineral lubricating oil and a small quantity of mixedorganic sulfonyl halides prepared from a mineral oil extract obtained byextraction of the oil with a preferential solvent for aromatichydrocarbons.

which extract is free from asphalt and boils substantially abovegasoline boiling range.

4. A substantiallynon-corrosive lubricant comprising a predominatingquantity of a mineral lubricating oil and a small quantity of mixedorganic sulfonyl halides prepared from an aromatic kerosene extractwhich is soluble in liquid S02. 1

5. A substantially non-corrosive lubricant comprising a minerallubricating oil containing less than 5% mixed organic sulfonyl halidesprepared from an aromatic normally liquid mineral oil fraction solublein liquid S02 and boiling substantially above gasoline boiling range.

6. A substantially non-corrosive lubricant comprising a minerallubricating oil containing between .1 and 2% of a mixture of organicsulionyl halides prepared from an aromatic normally liquid mineral oilfraction soluble in liquid 80: and boiling substantially above gasolineboiling range.

'7. A substantially non-corrosive lubricant comprising a predominatingquantity of a mineral lubricating oil and a small quantity of a mixtureof sulfonyl chlorides obtained by treating an aro-' matic normallyliquid mineral oil fraction soluble in liquid SO: and boilingsubstantially above gasoline boiling range with chlorsulfonic acid.

8. A substantially non-corrosive lubricant comprising a predominatingamount of a corrosive mineral lubricating oil and a small quantity of amixture 01' organic sulfonyl halides prepared from an aromatic normallyliquid mineral oil fraction soluble in liquid SO: and-boilingsubstantially above gasoline boiling range.

FRANZ RUDOLF MOSER. MARINUS CORNELIS TUYN.

